If you take 8 x 25 pders, you do not get either mortars, or your Pack 75's or HMS warspite.
How are you not taking deck slots into account?
If you don't take Warspite and you take the mortars, the Packs and all the 25's that is a grand total of 12 light artillery pieces for the entire match. Your number only goes down if you take Warspite.
This is not a lot of artillery. It just looks that way when looking at the x5 card.
101st gets 105mm and 75mm on top of mortars and off-map. Artillery is not its weakness. I don't play 3rd FSJ often at all so I don't remember what it has, but I'm sure it has some nice mortars and multiple off map options since that shit has rained on me incessantly.
101st relies on offmap which, as I said earlier, is another matter entirely. It has a total of 4 on map artillery pieces not counting the 60mm mortars. The pack howitzers are the same as 6th with the exception you can take 1 card of two in A, and the 105s you can only take 1 card of 2 iirc.
FSJ also relies on offmap, their onmap pieces consist of 1 card of 81mm mortar in A, and 1 card of GebH. 40 which is better than 25PDR, but has less range, and you can only get 2 of them max.
What you're proposing would essentially merge both an airborne and infantry deck together so that something like 352nd, 716th, or 17th could not hard counter it as it is supposed to (being artillery dedicated decks).
Again, let me repeat again airborne decks are not supposed to have strong artillery, what you propose would have them be as powerful as 2nd ID, or Scots that are dedicated artillery decks and pay for that by not also having a ridiculous airtab to boot. You pick one or the other, and 6th AB is picking the airtab.